Exposure to ocrelizumab resulted in a lowering of NfL levels to comparable to 118 healthy donors which established NfL ranges of 5.5–9.8 pg/mL for blood serum and 4.3–7.9 pg/mL for blood plasma. In this analysis, which included data from the phase 3 OBOE study, the donor range was defined as the 90th percentile of an age-matched healthy cohort.

“These analyses from the Ocrevus trials strengthen the evidence for pursuing neurofilament light chain as a potential biomarker of disease activity and progression in MS, including its potential to predict future disability outcomes,” said Amit Bar-Or, MD, FRCP, FAAN, FANA, chair, OBOE study Scientific Steering Committee, and chief, Multiple Sclerosis Division, Perelman School of Medicine, University of Pennsylvania, in a statement.

“Disease progression in MS can be challenging to identify without noticeable relapses or disability progression, and continued investigation into neurofilament light chain may help us better understand the underlying progression in all forms of this disease,” Bar-Or said.

The Genentech agent, which targets CD20+ B cells, was shown to reduce brain MRI and relapse activity, as well as disability progression in patients in the OPERA and ORATORIO trials. Using the Quanterix Advantage Kit in patients with relapsing (OPERA I: treatment, n=368; IFN β-1a, n=347) and primary progressive disease (ORATORIO: treatment, n=347; placebo, n=169). The findings showed that both plasma and sera levels were strongly correlated (r = 0.94).

Ocrelizumab was the first, and remains the only, agent approved for relapsing MS, active secondary and primary progressive MS, in addition to clinically isolated syndrome (CIS), approved in 2017 in the United States. It is dosed every 6 months, with upward of 120,000 individuals treated globally.